Variable stroke fuel pump



Jan. 3, 1933.-

A. M. BABlTcHl VARIABLE STROKE FUEL PUMP Filed'Julg 19, 1926 2 sheets-sheet 1 i I Il me/nto@ @fz/am mmf/a Jan.k3, 1933. A. M. BABITCH 1,893,215

VARIABLE STROKE FUEL PUMP Filed July 19, 192ev 2 sheets-sheet 2` wom? Patented Jan. .3, 1933 UNITED STATES ABRAHAM I. BABITCH, F FLINT, MICHIGAN VARIABLE s'rnoxE rum. rum

Application led July 19, 1926. Serial No.123,370.-

This invention relates to means for supplying fuel from a tank to the carburetor of a gas engine.

Among the objects of the invention are the following.

To make use of an engine operated diaphragm pump to supply the fuel.

To provide positive actuation for the pump on the suction stroke only.

To usel independent means, preferably a spring, to elfect the discharge movement.

To connect the pump with a iioat chamber and to so construct the operating mechanism that the pumping capacity is controlled by a float level which is in turn controlled by both the speed and the load of the engine.

To so construct the motor operating means for the pump that the positive suction stroke varies automatically from no movement when m no fuel is discharged to full stroke when maximum delivery 1s required.

The attainment of the above objects is accomplished by the use of the structure heredescribed and shown on the accompanym ing drawings.

In the drawings;

Figure 1 shows in front elevation an internal combustion engine with my invention applied thereto.

Figure 2 is a longitudinal vertical section through the pump mounted on the motor.

Figure 3 is a side elevation partly in section of modified form.

Figure 4 shows asecond modification in transverse section.

Figure 5 is a plan view of the modification shown in Figure 4, with the cover portion removed.

Referring by reference characters to the drawings, numeral 1 represents an internal combustion engine upon the front end of which is seen at 3 the cover plate of a water pump. Through this cover plate passes the shaft 5 which operates the pump. Two or more of the bolts 7 which secure the cover plate 3 to the motor block serve to hold arms 9 which are laterally extended from the fuel pump which constitutes the subject of this application.

5 The fuel pump is composed ofa pump body 11 and a cover 13. .The pumpbody l1 is hollowed out as shown at 15 and projecting within the hollowed out portion is an apertured boss 17. Between the pump body 11 and the cover 13 is secured, in any convenient man- 55 ner, a diaphragm 19, the vibratory reciprocations of which constitute the pumping means for the fuel. The diaphragm used is of long libre Egyptian cotton fabric especially treated to make it impervious to gasoline under considerable pressure. A flexible nonmetallic diaphragm of this kind will withstand considerable pressure without injury and give long service. A spring 21 within the recess 15 engages the under side of the G5 diaphragm and normally holds it in its upper-most position. Reciprocating through the boss 17 is a plunger rod 23 having reduced end 25. The reduced end passes through diaphragm 19 and through two metal plates 27, one on each side of the diaphragm. The diaphragm and the metal plates are held against the shoulder on plunger 23, formed by the reduced end 25, by means of a nut 29. The exhaust movement of the diaphragm is effected by the following mechanism.

31 is a push rod for a valve of the front cylinder. Secured to this push rod is a sleeve 33 against which rests Vthe forked ends 35 of a lever 37. This lever is pivoted at 39 to a. lower skirt portion of the pump body 1 1. Between the lower end of plunger 23 and the work end of lever 37 are a pair of links 41. These links are pivoted to the lever and plunger and to each other by pivot pins 43. The links also have projections which engage each other, as shown at 45, to prevent the links 41, coming into alignment. A pin 47 is passed through the push rod 31 and between thisY pin and the ends 35 of the lever 37 are placed two plates 49 and a spring 51. By this means the end 35 of the lever 37 is held yieldingly against the sleeve 33.

Within the pump body 11 there is an opening 53 having a reduced portion 55, a ball 57 is seated in this opening and is limited in its upward movement by a retainer '59 located beneath the diaphragm. 61 represents an opening for connection with a fuel pipe exl tending from the fuel tank. On the other side of the body member 11 there is a similar opening 63 communicating with an outlet 65 for the iloat reservoir. Within the opening 63 is located a spring 67 and a valve 69, there bein also a spring retainer 71 beneath' the diap ragm.

In the operation of the pump it will be understood that the suction stroke draws fuel in through`opening 61 past the ball valve 57 into the pump chamber above the diaphragm. Upon the exhaust stroke the fuel is forced past the spring valve 69 out through opening 65 to the float chamber. The spring 21 normally holds the diaphragm in its upper-most position but if the pressure of the fuel in the float chamber and the 'chamber of the pump `becomes high it operates againstl spring 21 to hold the diaphragm in a lower position. When the pump begins its action and there is little or no pressure in the pump chamber, spring 21 gives a full exhaust stroke. After the exhaust stroke the lever 37, by means of the links 41, produces a full suction stroke. 25 When the pressure in the pump chamber is sullicient to hold the diaphragm in its lowermost position against t e action of spring 21 there is obviously no exhaust stroke and the suction stroke does not effect the diaphragm but merely rocks the links 41, one upon the other. This lost motion connection is of particular importance in that it saves the diaphragm from continu l vibrations and thus greatly prolongs its 11 e. In this respect the arrangement provided is cpnsidered much superior toI certain known arrangements where a full pumping stroke is always permitted and a by-pass is provided to take care of the iiow of the fuel when the iioat chamber is full. l

In Figure 3 is shown a modified form of the invention wherein there is associated with the pump a fuel filter. Inthis form of the invention the pump member 11 is secured by fastening means 75 to a convenient part of the motor block. The internal details of the pump are substantially as in the form described. However, the pump bodly 11 and the head 13 are extended lateral y to provide for the filter. Within the lateral portion of the head 13 is a horizontal passage 77 communicating with a vertical passage 79.

The head 13 also has a vertical passage 81l from which the fuel goes to the pump and the outlet valve. Within the pump body there is a check valve, as at 83, engaging a seat 85 and held in position by a retainer 87. p The bottom portion of the extension of the pump body 11 also Ahas a projecting tubular portion 89 which is threaded to receive the threaded end of a bolt 91, the bolt has an axial opening 93 and radial opening 95 for affording communication from the head opening 77 to the interior of a cup, preferably of glass, 97. This glass cup is held in position against the under-side of the body portion extension by engagement'therewith at its open end the bottom of the cup being held by the head of the bolt. A filter 99 of suitable material is clamped betweenl the open end of the cup and the underside of the body extension. It will be seen that fuel entering at 77 passes through the assages 93 and 95 and from the cup 97 up t rough the check valve 83 and into the pump. In other respects this modification differs not at all from that already described.

In Figures 4 and 5 is shown another form of the invention. In this form the lower portion `of the pump body 111 is provided with a flange 113 and a reduced portion 115 for securing the pump body to' the motor block. 117 represents a cam shaft having a cam -119. This is the cam shaft that operates the push rods, one being shown at 121. The cam 119 rocks a lever 123 about a pivot 125. Upon the lever is a projection 127 engaged by a small plate 129 between which and a closure plate 131 at the bottom of the pump member 111 is a spring 133 for holding the lever normally against the cam 119. Two links 127 are arranged to produce the suction stroke of the pump and correspond in all particulars to the two links shown in Figure 2 and need no further description.

The plunger 21 extending through the part 17 and the spring 21 correspond also to the parts shown in Figure 2. In the body of the pump 111 there is provided on the under side thereof an opening 135. Within this recess 135 is a lter 137 held in position by a nut 139 threaded into the bottom of the opening 135. The passage for fuel 141 is shown at the side portion of the pump member 111. The fuel, after passing through the filter,

- travels up through an opening 143 in the top of the pump body 111. In this form of invention both valves are carried in the cover member. There is shown a valve seat 145 engaging a shoulder in an opening 147 extending into `the top of the cover. Within this opening 147 is a spring 149 engaging valve 151. Access to the valve for replacement or threaded cap 153. These parts are duplicated on the other side of the cover to form the exhaust valve from which there is an outlet 155 to the float chamber. This form of the invention has certain advantages over those already described, one of which consists in the ready access to the valves without removing the cover plate. The filter for fuel is also arranged in very compact relation.

Opening 157 may be provided to afford an air relief under diaphragm 19 so as to prevent pressure being `built up in chamber 15.

I claim:

1. In afuel pump for explosive motors, a cam shaft, a lever actuated thereby, a spring having a fixed abutment in said pump and acting upon said lever to hold it against repair is readily had by the removal of the said cam, a reciprocating member in said pump, a pair of links connecting said reciprocating member and said lever, means on said links to prevent their attaining a position of alignment.

2. A fuel pump comprising a chambered pump body, a non-metallic flexible member closing said chamber, inlet and outlet valves communicating with said chamber, a rotatable shaft having an element eccentric therewith, a member actuated by said eccentric element, and foldable means interposed between said last named member and said flexible member and operable under tension to produce a stroke of variable effect depending upon the pressure on the fuel in said chamber, and mechanism including resilient means independent of said foldable means associated with said flexible member for applying pressure thereto in the direction'of `the delivery stroke thereof.

3. A liquid pump comprising a chambered pump body, a flexible fabric member movable to vary the capacity of said chamber, an actuating member having a constant stroke, a constant stroke member driven by said actuating member, and constant lengthcollapsible means interposed between said driven member and said viexible member to Vcause a suction stroke of variable effect depending upon the pressure on the liquid in said chamber, said means including resilient means independent of said collapsible means associated with said flexible member for applying pressure thereto in the direction of the delivery stroke thereof.

4. In a pump, a member in said pump movable to make suction and discharge strokes, an operating member for said pump, means for producing a suction stroke only connecting said operating member and said movable pump member through which connect-ing means, when acting under tension, a suction stroke may be given said movable pump member, resilient means independent of said connecting means constantly active to give said pump member a discharge stroke, said connecting means being jolnted and foldable, all adjacent parts of said connecting means being in constant contact.

5. A low pressure fuel pump embodying a pumping element adapted to have a discharge stroke and a suction stroke, a rod connected thereto to actuate said element in the suction stroke only, an operating member, and a pair of links pivotally connected respectively to said rod and to sa1d operating member and to each other, the point of connection between said links being always at -one side of a line joining the points of connection of said links to the rod and operating member.

parts, said means comprising a link pivoted to each of said parts, said links also pivoted to each other, said last-named pivot movable transversely away from a line joining said first-named pivots under the influence of a force tending to cause the approach of said first-named pivots, together with a spring independent of said linkage constantly active to produce a discharge stroke. y

7 In combination, a power driven movable member, a pump member movable to make suction and discharge strokes, means connecting said members operable to make a suction stroke only, said means being collapsible and having all its parts-in constant contact, independent mechanism to produce a discharge stroke, said first-named means being operable when in tension to produce a suction stroke and free to collapse when under compression.

8. In combination, a power driven movable member, a pump member movable to make suction and discharge strokes, means connecting said members operable to make a suction stroke only, said means being collapsible and having al1 its parts in constant contact, independent mechanism to produce va discharge stroke, said first-named means being operable when in tension to produce a suctionv stroke and free to collapse when under compression, said means comprising jointed links, said links having surfaces adjacent their common pivot to engage each other tangentially and constitute in effect a rigid link before reaching alignment.

9. In combination, a power driven movable member, a pump member movable to make suction and discharge strokes, means connecting said members operable to make a suction stroke only, said means being collapsible and having all its parts in constant contact, independent mechanism to produce a discharge stroke, said first-named means being operable when in tensionv to produce a suction stroke and free to collapse when un- 'der compression, said means comprising jointed'links, said links having one a plain surface and the 'other a curved surface, said surfaces positioned to engage tangentially and prevent link alignment.

10. In a liquid pump, means including a flexible wall forming a variable volume chamber, `driven means having a constant stroke, power actuated means driven thereby, means foldable to an extent dependent upon the quantity of liquid required to beV discharged and independent of the speed of the driven means, said foldable means connecting said power actuated means and said flexible wall whereby there is produced at times a suction stroke and yielding means independent of the foldable means constantly acting upon the flexible wall and tending at all times to produce a discharge stroke.

11. A fuel pum' comprisin a um in chamber, a pumpinlg member ingthe hanibelg, means for operating the pumping member comprising a jointed linkage connected at 5 one end with said pumping member, an actuating' lever connected to the opposite end of the linkage whereby the pumping member is positively actuated by the movement of the lever in the direction for extending the linkage to pull the pumping member in the direction of said lever movement, a spring reacting between the casing and said pumping member'for resisting such pull and giving the pumping member its opposite movement,

and means associated with the linkage preventing the pivots of the linkage coming into alignment in the action of the lever for straightening the linkage.

In testimony whereo I aix m signature.

A. M. B BITCH. 

